Medical devices may be external or implanted. Implantable medical devices (IMDs) may serve a wide variety of functions, such as sensing one or more parameters of a patient, delivering one or more therapies to the patient, or a combination of these and other functions. An IMD may deliver therapy to, and/or monitor a physiological condition of, a variety of organs, nerves, muscles, tissues or vasculatures of the patient, such as the heart, brain, stomach, spinal cord, pelvic floor, or the like. The therapy provided by the IMD may include electrical stimulation therapy, drug delivery therapy or the like.
The IMD may include a power source such as a battery. The power source may be configured to provide power for the IMD to execute the functions for which the IMD was designed. In some examples, the power source may be rechargeable. The power source may be rechargeable through the use of coils that are configured to induce a current that is then channeled into the power source.
The IMD may also transmit communications to and/or receive communications from another device via wireless telemetry. The IMD may transmit and/or receive communications with another device that is implanted, attached to (e.g., worn by) the patient or otherwise located near the patient, or remote from the patient. The communications may include information related to a condition of the patient, such as physiological signals measured by one or more sensors, information related to a therapy delivered to the patient, or information that may be used to control or configure a therapy to be delivered to the patient or physiological signal measurement. The IMD may transmit and/or receive information using any of a variety of wireless communication techniques, including inductive telemetry, magnetic telemetry, radio frequency (RF) telemetry, or the like.